1. Field of the Invention
This invention relates to an ice-cream machine of a limited capacity, in particular as suitable for the needs of a family, a small community and the like, which will be called "ice-cream machine for family use".
More in detail, this invention relates to an ice-cream machine for family use having a greater usefulness and operating efficiency in comparison with the ice-cream machines for family use known up to now.
2. Description of the Prior Art
Ice-cream machines of reduced capacity, suitable for the preparation of an ice-cream quantity ranging between 1 and 2 kilos and therefore suitable for the needs of a family, a small community and the like, are already known. Said ice-cream machines generally comprise a cylindrical whipping vessel with vertical axis, the walls of which are in conditions of thermal exchange with the evaporator of a refrigerating circuit built in the ice-cream machine itself. Inside the whipping vessel there is provided a stirrer for the mass to be freezed, which is rotated by a shaft coaxial to the vessel itself and actuated by an electric motor, which is comprised in the ice-cream machine as well. The function of the stirrer is to mix the mass to be freezed and to put it in contact with the cooled walls of the whipping vessel so that the desired thermal exchange takes place.
One of the reasons for the commercial success of said small ice-cream machines is due to their limited size and their low cost.
These two characteristics, however, involve the use of motors with reduced power and consequently the ice-cream machine performances are strictly dependent upon the presence of optimal conditions of cold transmission between the mass to be freezed and the whipping vessel walls as well as of optimal stirring conditions.
In others words, the quantity and time of ice-cream formation may undergo decay and considerable delay, respectively, if during the ice-cream machine operation, conditions different from the optimal ones occur. For example the formation of ice scales on the vessel walls interfers with the stirrer blades and tends to slow down and sometimes even to block the stirrer rotation. Moreover, the mass to be freezed often tends to accumulate in the bottom area of the whipping vessel and in this case cold transmission is strongly limited, in that the top section of the vertical wall of the whipping vessel is not interested by the mass to be freezed.